Media Fragment URIs

<!-- Play the range 10 seconds through 20 seconds. -->
<video src="http://foo.com/video.ogg#t=10,20"></video>
<!-- Play from the beginning through 10.5 seconds. -->
<video src="http://foo.com/video.ogg#t=,10.5"></video>
<!-- Play from the beginning through two hours. -->
<video src="http://foo.com/video.ogg#t=,02:00:00"></video>
<!-- Start playing at 60s, through to end. -->
<video src="http://foo.com/video.ogg#t=60,"></video>